1. Field of the Invention
The present invention relates to a radiographic image detection apparatus that obtains a plurality of radiographic images by changing the positions of a radiation source and a radiographic image detector and by irradiating a subject with radiation.
2. Description of the Related Art
Conventionally, radiography has been performed on a predetermined region of a patient to obtain radiographic images of the region from a plurality of angles (directions) so that the patient is diagnosed by using the obtained radiographic images. Especially, in medical diagnosis, the same region of the patient is radiographed periodically to observe the progress and the condition of the disease or the like in many cases. Therefore, it is desirable that the angle of radiography in each periodic radiography operation is the same as the angle of radiography performed on the same patient in the past. Meanwhile, the sex, the height and the like of every patient (a person to be examined or radiographed, a subject) differ from each other. Therefore, when radiography is performed, it is necessary to finely adjust the position of the radiation source and the position of the radiographic image detector for each patient.
Here, a method for positioning a radiation source and a radiographic image detector when radiography is periodically performed has been proposed (please refer to Japanese Unexamined Patent Publication No. 11(1999)-244272 (Patent Literature 1), for example). In the method, the positions in the past radiography are stored, and the stored positions are used to position the radiation source and the radiographic image detector when a periodic radiography operation is performed. Specifically, in Patent Literature 1, the order of radiography and the position of the radiographic image detector or the like are stored in a header of a radiographic image obtained by radiography. When radiography is performed next time, the stored information is read out from the header of the radiographic image, and the radiographic image detector or the like is positioned.
In Patent Literature 1, efficient radiography may be performed on a patient who was radiographed in the past. However, when a patient is radiographed for the first time, an operator (a radiographer, a radiological technician, or the like) needs to adjust the position of the radiation source and the position of the radiographic image detector. Even when radiography is performed on the patient for the first time, it is desirable that the radiation source and the radiographic image detector are positioned in a short time period to perform efficient radiography.